Digital lighting technologies, i.e., illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications. Some of the fixtures embodying these sources feature a lighting module, including one or more LEDs capable of producing different colors, e.g., red, green, and blue, as well as a processor for independently controlling the output of the LEDs in order to generate a variety of colors and color-changing lighting effects, for example, as discussed in detail in U.S. Pat. Nos. 6,016,038 and 6,211,626, incorporated herein by reference.
Dynamic lighting effects may be used to mimic various lighting phenomena, such as candlelight flicker or ripples of water. Some dynamic lighting effects may most effectively mimic lighting phenomena when the light that forms them is emitted with particular lighting properties. For example, candlelight flicker is best mimicked at relatively low levels of brightness. While a chandelier of LED-based lighting units may be aesthetically appealing when those lights mimic candles, it may also be desirable on occasion to use the chandelier to provide functional lighting, which is typically much brighter than candlelight. LED controllers that are capable of handling low root mean square (“RMS”) voltages can be complicated and/or expensive, and may not be suitable for a plurality of relatively high-powered LED bulbs, especially when the high-powered LED light bulbs are not necessary for low level dynamic effects such as mimicking candlelight. Thus, there is a need in the art to provide a lighting unit that is both capable of creating dynamic lighting effects such as candlelight and that is also capable of providing functional lighting, without the need for complicated and/or expensive circuitry.